Denver and the West

Complex world of soil studied by Colorado State University scientists

Dishing the Dirt. Colorado State University lab supervisor Cecilia Tomasel looks at microscopic plectus
worms in a soil sample at the Soil Biodiversity and Ecosystem Functioning Lab. Scientists are keeping their
eyes to the ground, studying the microorganisms that affect soil health. (Helen H. Richardson, The Denver Post)

FORT COLLINS — As scientist Diana Wall and her team peered at them through microscopes, the trapped tiny creatures feasted on morsels in dirt.

A nematode's innards bulged full of carbon and nitrogen. A water bear pulsed, devouring algae. Spiderlike mites and springtails jumped — the underground equivalents of zebras and giraffes.

Exploits of these subsurface organisms are a growing preoccupation for scientists because the ecological oomph of soils that people depend on for food, health and water is eroding. Understanding how the tiny creatures work may help restore soil fertility and stop deadly sicknesses.

Underground World. Scientists use a six-step process involving water, screens and a centrifuge to separate nematodes microscopic worms out of soil samples collected from all over the world. This soil came from a site in the Chihuahuan Desert in Las Cruces, N.M. Colorado State University scientist Diana Wall and her team are studying the "soil frontier," trying to better understand the diverse ecosystems underground.
(Helen H. Richardson, The Denver Post)

"There are huge quantities of organisms in soils that are working for us at no cost — to control pests and pathogens, cleanse water, aerate soils, store carbon, maintain soil fertility, prevent erosion, and maintain healthy soils," Wall said at her lab at Colorado State University.

Today, at least three United Nations agreements address soil health, pulling Wall and a global network of scientists together to solve the puzzle of how people can draw more benefits from the world's shrinking areas of open land, as fire, flood, intensive farming and development diminish fertility.

"We need to know how to manage the land better," Wall said. "We're putting more pressure on land. We need to bring some people to the table. Are we starting to give up some of our richness when we develop urban areas?"

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Resource overseers from China to Chad now are embracing the maxim that President Franklin Roosevelt conveyed during the Dust Bowl: The nation that destroys its soil destroys itself.

This new interest drives researchers to understand how the underground churning of soil microorganisms cycles carbon, stabilizes soils, and controls pests and pathogens and invasive species.

A global consortium of scientists has embarked on digitally mapping Earth's soils and soil properties, starting in Africa with the help of an $18 million Gates Foundation grant.

The Researcher. Diana Wall stands in the Soil Biodiversity and Ecosystem Functioning Lab at Colorado State University in Fort Collins. She and her team have collected microorganisms nematodes, mites and other "underground workers" in 500 samples of soil from around the globe. They keep the samples in freezers inside a restricted-access CSU lab and are analyzing how much and how quickly the microscopic worms eat and how they cycle carbon and stabilize soils.
(Helen H. Richardson, The Denver Post )

But studying microorganisms is especially difficult because nematodes and others are so small. Herding enough of them together for research has proved tricky.

The National Science Foundation deployed Wall and her CSU team to fan out from Antarctica to Kenya to collect dirt. Over a decade, they've amassed 500 samples scooped from faraway forests, edges of frozen lakes and dry valleys — all stored in 22 freezers in a restricted-access lab at Fort Collins.

On a recent morning, they laid out some of that dirt beneath microscopes, working to isolate and count nematodes, one by one.

The goal is to determine exactly how much food — carbon and nitrogen — nematodes consume and how quickly they eat.

Lab supervisor Cecilia Tomasel led the process of stuffing each nematode into a bullet-sized tin cup. Trays of cups are hauled to Kansas for analysis in a spectrometer.

Microscopes have been around since 1672, but advances in recent years, including the ability to read DNA, have enabled a more precise study of the lives of underground organisms.

The emerging evidence, Wall said, suggests that grave harm results from intensive use and misuse of soils and the sealing of soil beneath pavement in cities.

Starting in Europe, city planners are launching programs to nurture microorganisms because of their role in removing pollution, purifying water and controlling erosion.

Frequent discoveries of new microorganisms and other advances have helped draw an international team of scientists to the CSU lab.

"Soil's like a frontier in science," said Martijn Vandegehuchte, 27, from Belgium. "People are just starting to realize what is there and what it is doing for humans."

Team discoveries also have challenged conventional understanding soil-level biodiversity. For example, Wall and an NSF team found that while diversity of above-ground species is greater at the equator than Earth's poles, there are similar numbers of nematodes, mites and springtails no matter at what latitude the samples are taken.

It's "a paradigm shift" for those who want to understand life, said Matthew Kane, the NSF's director for ecosystem sciences.

"It's the tiny things that outweigh the larger things. If we think we're going to understand life by just watching things like elephants and zebras, we'd miss the greater story — the really tiny forms of life that make the rest of life possible," Kane said.

"If our planet is changing and we're going to understand what's going to happen in the future, we have to have a basic understanding of how life works in the first place."

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